Persistent entanglement in 'promoted' states

Speaker : Arun Kannawadi

2015-07-01

Abstract :

Entanglement is the "spooky" property in quantum systems that makes quantum computation possible. In a typical multi-qubit system, the entanglement is seen within blocks of qubits that scale with the system size and any pair or triplet of qubits are almost never entangled. After introducing the measures of entanglement briefly, I will explain how in a special class of states, namely the 'definite-particle' states, pairs of qubits are entangled and how the expected entanglement
scales with the number of qubits.Then I will move on to explain 'promoted states', a special subset of definite-particle states, that also happen to arise naturally in spin-systems. Using random promoted states, I will show that such states exhibit relatively high entanglement between any pairs of qubits and compare the theoretical results with the simulations on the 'promoted eigenstates' of long-ranged and short-ranged spin-glass Hamiltonians.